CLUSTER ANALYSIS IDENTIFIES VARIABLES RELATED TO PROGNOSIS OF BREAST CANCER DISEASE

This work presents a cluster analysis approach aiming to determine distinct groups based on clinicopathological data from patients with breast cancer (BC). For this purpose, the clinical variables were considered: age at diagnosis, weight, height, lymph nodal invasion (LN), tumor-node-metastasis (TNM) staging and body mass index (BMI). Ward's hierarchical clustering algorithm was used to form specific groups. Based on this, BC patients were separated into four groups. The Kruskal-Wallis test was performed to assess the differences among the clusters. The intensity of the influence of variables on the prognosis of BC was also evaluated by calculating the Spearman's correlation. Positive correlations were obtained between weight and BMI, TNM and LN invasion in all analyzes. Negative correlations between BMI and height were obtained in some of the analyzes. Finally, a new correlation was obtained, based on this approach, between weight and TNM, demonstrating that the trophic-adipose status of BC patients can be directly related to disease staging.

Predicting the Productivity Enhancement After Applying Acid Fracturing Treatments in Naturally Fractured Reservoirs Utilizing Artificial Neural Network

Acid fracturing treatments are conducted to increase the productivity of naturally fractured reservoirs. The treatment performance depends on several parameters such as reservoir properties and treatment conditions. Different approaches are available to estimate the efficacy of acid fracturing stimulations. However, a limited number of models were developed considering the presence of natural fractures (NFs) in the hydrocarbon reservoirs. This work aims to develop an efficient model to estimate the effectiveness of acid fracturing treatment in naturally fractured reservoirs utilizing an artificial neural network (ANN) technique. In this study, the improvement in hydrocarbon productivity due to applying acid fracturing treatment is estimated, and the interactions between the natural fractures and the induced ones are considered. More than 3000 scenarios of reservoir properties and treatment parameters were used to build and validate the ANN model. The developed model considers reservoir and treatment parameters such as formation permeability, injection rate, natural fracture spacing, and treatment volume. Furthermore, percentage error and correlation coefficient were determined to assess the model prediction performance. The proposed model shows very effective performance in predicting the performance of acid fracturing treatments. A percentage error of 6.3 % and a correlation coefficient of 0.94 were obtained for the testing datasets. Furthermore, a new correlation was developed based on the optimized AI model. The developed correlation provides an accurate and quick prediction for productivity improvement. Validation data were used to evaluate the reliability of the new equation, where a 6.8% average absolute error and 0.93 correlation coefficient were achieved, indicating the high reliability of the proposed correlation. The novelty of this work is developing a robust and reliable model for predicting the productivity improvement for acid fracturing treatment in naturally fractured reservoirs. The new correlation can be utilized in improving the treatment design for naturally fractured reservoirs by providing quick and reliable estimations.

Exploring Diffuse Radio Emission in the Southern Sky

<p>This thesis investigates currently observed correlations between the thermal and non-thermal (radio halos) components of galaxy clusters, and seeks to verify the reliability of the proposed radio halo scaling relations presented in the literature. It employs a two-pronged approach: 1) a statistical examination of 15 galaxy clusters; and 2) detailed multi-wavelength analysis of individual objects of interest. We first investigated radio data for 15 galaxy clusters drawn from the parent REXCESS sample observed with the ATCA at 1.4 GHz to conduct a radio halo survey. Examination of available and re-processed low resolution images revealed cluster-scale diffuse objects in three clusters. One was a radio halo candidate in Abell 3888 (A3888), with the two remaining diffuse sources being radio relic candidates. Follow-up observations of the candidate clusters were performed in July and December 2011, and March 2012, with the upgraded ATCA (CABB). Radio observations with CABB in different array configurations were used to provide the required resolution and sensitivity to a wider range of angular scales to probe the candidate diffuse sources. Examination of the final CABB images confirmed the existence of the radio halo in A3888; however, the remaining candidates were found to be a head-tail galaxy and a very bright radio galaxy with extended emission. As this thesis presents some of the earliest CABB observations, new data reduction and imaging procedures were necessarily developed and presented here. The statistical component of this thesis uses a halo sample obtained from the combined detection of this work and the literature to derive new correlations between the cluster observables and the radio halo power. The new correlation between the X-ray luminosity and radio halo power derived here is flatter than the previous correlation in the literature, suggesting that massive clusters may host lower power halos than previously thought. In addition, we derived the upper limits of the undetected power of possible radio halos for our non-halo clusters via injection of fake radio halos into the UV data. Our derived upper limits with respect to the anticipated halo powers according to the previous and new correlations and their interpretations are discussed in the thesis. The distribution of the combined upper limits (this work and the literature) compared to our new correlation shows no sign of the strong bi-modality found in the literature. As previously mentioned, we detected a giant radio halo in A3888. We observed A3888 with the AAOmega spectrograph to infer the dynamics of the cluster. We measured the spectra of 254 galaxies within a 300 radius from the core of A3888 and combined these data with the available literature redshifts in the region. We identified 71 member galaxies of A3888 and examined the density contours, which indicated that the distribution of the member galaxies is elongated along an east-west axis. This elongation might be indicative of dynamical interactions in the cluster; however, there is no statistically significant deviation from Gaussianity in the velocity data. We then carried out a Lee-Fitchett 3D substructure test and found that A3888 is bimodal and has two subgroups. The head-tail galaxy mentioned earlier in one of the clusters was originally thought to be a radio relic candidate. Owing to available broadband polarimetric data and well-separated jets of the head-tail galaxy, we investigated the magnetic field direction of the head-tail galaxy and conclude it is highly likely that a helical magnetic field is present in the jets. We present the high-resolution images of our 15 clusters and create a catalogue of the detected sources. Finally, we discuss concerns with the current radio halo detections in the literature, and how radio halo surveys could be designed in the future to yield unbiased results.</p>

Exploring Diffuse Radio Emission in the Southern Sky

<p>This thesis investigates currently observed correlations between the thermal and non-thermal (radio halos) components of galaxy clusters, and seeks to verify the reliability of the proposed radio halo scaling relations presented in the literature. It employs a two-pronged approach: 1) a statistical examination of 15 galaxy clusters; and 2) detailed multi-wavelength analysis of individual objects of interest. We first investigated radio data for 15 galaxy clusters drawn from the parent REXCESS sample observed with the ATCA at 1.4 GHz to conduct a radio halo survey. Examination of available and re-processed low resolution images revealed cluster-scale diffuse objects in three clusters. One was a radio halo candidate in Abell 3888 (A3888), with the two remaining diffuse sources being radio relic candidates. Follow-up observations of the candidate clusters were performed in July and December 2011, and March 2012, with the upgraded ATCA (CABB). Radio observations with CABB in different array configurations were used to provide the required resolution and sensitivity to a wider range of angular scales to probe the candidate diffuse sources. Examination of the final CABB images confirmed the existence of the radio halo in A3888; however, the remaining candidates were found to be a head-tail galaxy and a very bright radio galaxy with extended emission. As this thesis presents some of the earliest CABB observations, new data reduction and imaging procedures were necessarily developed and presented here. The statistical component of this thesis uses a halo sample obtained from the combined detection of this work and the literature to derive new correlations between the cluster observables and the radio halo power. The new correlation between the X-ray luminosity and radio halo power derived here is flatter than the previous correlation in the literature, suggesting that massive clusters may host lower power halos than previously thought. In addition, we derived the upper limits of the undetected power of possible radio halos for our non-halo clusters via injection of fake radio halos into the UV data. Our derived upper limits with respect to the anticipated halo powers according to the previous and new correlations and their interpretations are discussed in the thesis. The distribution of the combined upper limits (this work and the literature) compared to our new correlation shows no sign of the strong bi-modality found in the literature. As previously mentioned, we detected a giant radio halo in A3888. We observed A3888 with the AAOmega spectrograph to infer the dynamics of the cluster. We measured the spectra of 254 galaxies within a 300 radius from the core of A3888 and combined these data with the available literature redshifts in the region. We identified 71 member galaxies of A3888 and examined the density contours, which indicated that the distribution of the member galaxies is elongated along an east-west axis. This elongation might be indicative of dynamical interactions in the cluster; however, there is no statistically significant deviation from Gaussianity in the velocity data. We then carried out a Lee-Fitchett 3D substructure test and found that A3888 is bimodal and has two subgroups. The head-tail galaxy mentioned earlier in one of the clusters was originally thought to be a radio relic candidate. Owing to available broadband polarimetric data and well-separated jets of the head-tail galaxy, we investigated the magnetic field direction of the head-tail galaxy and conclude it is highly likely that a helical magnetic field is present in the jets. We present the high-resolution images of our 15 clusters and create a catalogue of the detected sources. Finally, we discuss concerns with the current radio halo detections in the literature, and how radio halo surveys could be designed in the future to yield unbiased results.</p>

Low -parametric equation for calculating the viscosity coefficient of nitrogen in liquid, gas and fluid states

The formulation for the viscosity coefficient of nitrogen is obtained. In the developed equation the dependence of the residua viscosity of various states of substance on the internal energy density is used. The new correlation represents the viscosity of nitrogen at temperatures from 70 K to 1000 K and pressures of up to 50 MPa within the limits of experimental uncertainties.

Free Convective Heat Transfer in a Closed Gap between Concentric Semi-Hemispheres

Free convective heat transfer in the closed gap between concentric semi-hemispheres is quantified by means of a numerical approach based on the volume control method using the SIMPLE algorithm. The average Nusselt number is determined for several configurations obtained by varying the cavity’s aspect ratio between 0.15 and 1.5, while the Rayleigh number varies within the 5.33 × 103–4.50 × 108 range. The results show that the correlations available in the literature dealing with concentric whole spheres cannot be used for the configuration treated here. The new correlation between the Nusselt and Rayleigh numbers proposed in this work can be applied in various engineering sectors, such as in the electronic packaging considered in this present work, buildings, and architecture.